Distribution of naive and memory T-cells in photoprovoked and spontaneous skin lesions of discoid lupus erythematosus and polymorphous light eruption

Immune response to ultraviolet radiation-modified skin antigens has been su ggested as a pathomechanism of skin lesions in discoid lupus erythematosus and polymorphous light eruption. In order to elucidate the role of T-lympho cyte subsets in this response, We studied the distribution of CD45RO(+), CD 45RA(+) and CD31(+) cells and the endothelial expression of adhesion molecu les E-selectin/P-selectin, intercellular adhesion molecule-1 and CD31 antig en in photoprovoked and spontaneous skin lesions. Typically, CD45RA(+) cell s were the prevailing inflammatory cell population of discoid lupus erythem atosus, whereas CD45RO(+) cells prevailed in both diseases and in healthy c ontrols. Epidermotrophism of any T-cell subsets was more typical of discoid lupus erythematosus, whereas no major differences in endothelial adhesion molecule expression was found between the 2 diseases. Strong keratinocyte I CAM-1 expression was associated with adjacent CD45RO(+) cell infiltrates, n ot with CD45RA(+) or CD31(+) cell infiltrates. We conclude that the cellula r immune response to UV radiation is dissimilar in discoid lupus erythemato sus and polymorphous light eruption.